Feasibility of Ion Exchange Membranes to Control pH during Electro-Osmotic Consolidation

Abstract

Electro-osmosis is an established method of consolidating soft fine-grained soils. Its efficiency is controlled by the electrical resistance of the soil-electrode system. Because of an increase in soil electrical resistance during treatment, its cost efficiency is reduced, limiting the widespread use of this technique, especially in developed nations. One of the main causes of electrical resistance is hydrolysis of water molecules around the electrodes. The acidification of the anode, in particular, reduces the negative surface charge of clay particles and, thus, the zeta potential. According to the Helmholtz-Smoluchowski model, the zeta potential is directly proportional to the electro-osmotic permeability. This article studies the use of ion exchange membranes to assess their ability to prevent flow of hydrogen ions into the soil. The test with an anion exchange membrane showed minimal change of the pH in the soil around the anode compared to a control, which is better for electro-osmotic consolidation.